Try hitting through the ball slightly on the upswing.
Putts stroked in the normal way have almost no spin as they leave the putterface, the ball essentially skidding along the ground for a short distance.
But when greens are unusually bumpy, the lack of initial spin can become a problem in that the ball might contact something that deflects it off line before it develops its own inertia. And, of course, that fraction of an inch the ball is knocked off line early can become a matter of feet by the time it reaches the hole.
To help solve this control problem, I suggest you try hitting through the ball slightly on the upswing.
You'll find that this change in the stroke will give the ball a truer roll almost from the moment it leaves the putterface, thereby diminishing the effect of irregularities on the green.
HIT IT SOLIDLY WITH SQUARE TO SQUARE
got to the tournament.
Over my career I was sometimes a square-to-square putter, sometimes an open-to-closed putter, and sometimes a closed-to-open putter.
In 1972, I recall winning seven times--including the Masters and U.S. Open--using the three different patterns of stroke. But I didn't know which stroke I would use until I got to the tournament venue and checked out the green conditions.
When putting square to square--on true and fairly fast greens--I swing the putter away from and back through the ball without any rotation of the face.
When putting open to closed--which I usually use on poor or slow or grainy greens--I allow the putterface to rotate slightly clockwise on the back-stroke and counterclockwise through the ball.
My closed-to-open stroke produces a soft or gentle sort of impact for extremely fast putts.